For some years mechanical power systems have been known of the type able to continually change their rate of speed, generally in the range of medium and low power, usually obtained by continual variation of the ratio of the radiuses of two pulleys, in particular in those applications in which their characteristics lend themselves to this type of system, such as agricultural machinery and also the “gear box” of all kinds of vehicles.
Another related registration is U.S. Pat. No. 6,517,461 in the name of Nissan Motor Co., which consists of a transmission mechanism incorporating a helical gear which meshes with a final outlet gear which transmits rotation to the final mechanism of the shaft, with the sides of the teeth and the final outlet the final output shaft of a ring gear arranged in such a way that the force exercised on the ring by a planetary gear and the force exercised by the transmission act in opposite directions.
In the automotive field patent ES 2068047 may also be cited: “Continual mechanical gear change” which incorporates a pair of tapered pulleys, with an intermediate flexible transmission element together with a power transmission mechanism and a planetary gear arranged at the outlet connecting, the first pulley to the entry shaft of the system, while the second is connected to the entry shaft of the power transmission mechanism, the outlet shaft of which activates one of the planetary elements while the remaining elements are related respectively with the entry shaft and the outlet shaft of the device which is the object of the invention, in various arrangements and distributions of these elements.
Despite its validity and opportunity, this invention generates a discontinuity in the transmission relation between the pair of pulleys, in particular with respect to the shaft speed of the entry and outlet shafts, which leads to a need to change the direction of the outlet shaft when the speed is still relatively high, with subsequent disadvantages in the long term with respect to stress and wear etc.
The applicant is unaware of mechanical transmissions which are genuinely continual and with a high range of variation of revolutions of the outlet shaft, in addition to high torque, which resolve the aforementioned problem by incorporating a differential mechanism which dispenses with the need for reverse gear and clutch, and which also resolves this problem with the simplicity and effectiveness of the invention described herein.